Question:
What does the following Informix error message mean, and what can I do to prevent it:
"could not position within a file via an index"
It happens when I am doing multiple inserts on one HTML page.
Answer:
This error typically represents a concurrency problem within the database. When you are doing multiple inserts, the first insert is locking resources that the other inserts need. You can approach the problem in several ways, and you should look at all of them.
First, keep your transactions very short. For example, if you are opening a transaction and waiting for the user to push a button, you may be getting this problem. Instead, have the button push begin the transaction, do the insert, and commit the work. Don’t wait for the user to decide what to do next.
Look at the locking level of the table into which you’re inserting. If it gets frequent inserts, change the locking mode to row locking rather than the default page locking. Finally, you may be able to reduce the impact of the problem by setting wait mode to 30 or so and providing logic in the application that intercepts this error message and retries it after a few seconds’ wait.
